Imperial College London
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Professor Nick Buenfeld

Faculty of Engineering, Department of Civil and Environmental Engineering

Professor of Concrete Structures
 
 
 
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Contact

 

n.buenfeld Website

 
 
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Location

 

228BSkempton BuildingSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Muslim:2020:10.1617/s11527-020-01591-9,
author = {Muslim, F and Wong, H and Cheng, G and Alexandrou, C and Liu, B and Buenfeld, N},
doi = {10.1617/s11527-020-01591-9},
journal = {Materials and Structures},
title = {Combined effects of vertical spacers and segregation on mass transport properties of reinforced concrete},
url = {http://dx.doi.org/10.1617/s11527-020-01591-9},
volume = {53},
year = {2020}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - All concrete structures contain reinforcement spacers, and deep sections can be affected by bleeding and segregation without displaying visible indications during casting. However, their effects on mass transport and long-term durability are not well studied. In this paper, reinforced concrete columns were prepared with plastic and cementitious spacers to achieve 50 mm cover, and compacted at different vibration frequencies and durations. 28d cured samples were extracted along the height, conditioned to equilibrium (21 °C, 75% RH or 50 °C, 7% RH), and then subjected to water absorption, electrical conduction, epoxy impregnation and fluorescence imaging. Samples from the top of the column consistently gave higher accessible porosity and mass transport compared to samples from the bottom. Presence of spacers caused additional increases in mass transport because of preferential flow through the spacer-concrete interface which is more porous and microcracked compared to bulk concrete farther away. Image analysis on cross-sections showed that the columns experienced some aggregate segregation despite care taken to avoid over-compaction. The resistance of concrete to ingress of aggressive agents decreases with increasing height due to the combined negative effects of reinforcement spacers and segregation.
AU  - Muslim,F
AU  - Wong,H
AU  - Cheng,G
AU  - Alexandrou,C
AU  - Liu,B
AU  - Buenfeld,N
DO  - 10.1617/s11527-020-01591-9
PY  - 2020///
SN  - 1359-5997
TI  - Combined effects of vertical spacers and segregation on mass transport properties of reinforced concrete
T2  - Materials and Structures
UR  - http://dx.doi.org/10.1617/s11527-020-01591-9
UR  - http://hdl.handle.net/10044/1/84910
VL  - 53
ER  -
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